Speaker



FIG. 1 is a front perspective view of a speaker;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof, the left side elevational view thereof being a mirror image; and,

FIG. 5 is a top plan view thereof.

The bottom of the speaker, not shown, forms no part of the claimed design. 

The ornamental design for a speaker, as shown and described. 